Bath based valve control systems specialist Rotork was recently contracted to supply valve actuation control systems for a major airport expansion project in Saudi Arabia. Over the next five years, the Saudi General Authority for Civil Aviation plans a significant development of the King Abdul Aziz International Airport in Jeddah, which will enable it to accommodate 35 million passengers a year. Included in this is a new terminal with 74 jet bridges that will receive aircraft of all sizes, including the new Airbus A380.
Rotork is supplying 120 of its IQPro intelligent electric valve actuators to Cameron Valves for the control of double-block-and-bleed valves that are installed on the airport’s hydrant A380 refuelling network. Two Rotork Pakscan master stations have also been supplied, and these will be used to control and monitor the actuators and associated equipment via an industrial Ethernet network, supervised by Korenix JetNet 5010G Gigabit managed Ethernet switches. These provide dual Ethernet redundancy for each of the two master stations, one of which remains in a hot standby condition to take over in the event of failure. The entire dual redundant system is housed in a single enclosure.
Korenix switches were eventually selected from an initial list of four suppliers’ products, because they offer the fastest available network recovery time - less than 5ms. As Mike Howard, senior systems sales engineer at Rotork recalls, in acceptance tests, the Korenix switch was the only one that conformed to the redundancy specifications. “It was also very cost-effective,” he said.
According to Mr Howard, many of Rotork’s control systems are used in critical applications such as hydrocarbon processing plants. Security and minimal downtime are what matters to customers, he says, and so a high proportion of the company’s control systems is configured in hot standby mode. Moreover, technical assistance is often not immediately available at remotely located installations, so redundancy is a prerequisite. Mr Howard takes up the story.
“When we used a single Ethernet switch connected to both sides of our master station, everything worked well. However, when we introduced a second Ethernet switch to provide the dual redundancy, we began to experience significant Ethernet ‘broadcast storms’ or network freeze, where the control networks became swamped with Ethernet messages.” The solution to this problem was provided by Korenix.
The JetNet 5010G is the only industrial Ethernet switch on the market that provides three Gigabit SFP connections in one modular design. Most competing suppliers can only offer two SFP connections per switch at best, and users need to purchase three separate SFP models and three separate RJ45 models to achieve the desired connectivity.
For most industrial applications, the most common redundant Ethernet LAN topology is a ‘ring’. Korenix’s Multi Super Ring is a set of five patented technologies that can work individually or in combination, and in an incredibly simple way as far as the user is concerned. One of these is Rapid Super Ring II technology, which is designed to meet the fast recovery times demanded by industrial ring networks. Interoperability between different ring topologies and vendors is critical. The JetNet 5010G works with all ‘open’ network topologies, enabling companies to integrate the device quickly and easily into their existing IT infrastructure at minimal cost and disruption. Korenix’s ‘ANY Ring’ technology enables integration with a number of third party ring systems, which saves time and money.
Another of Korenix’s technologies is ‘Dual Homing II’, which connects the Super Ring to other ring redundancy protocols, such as RSTP (Rapid Spanning Tree Protocol). This ensures that the rings communicate well and the dual homing paths can back each other up, providing a disconnect time of 50 milliseconds and a reconnect time of 0 milliseconds. For example, the user, in just two mouse-clicks, can auto-select one Dual Homing uplink path as an ‘Active Link’, while the other is a ‘hot standby’ link.
To further reduce recovery time and increase link capacity, the JetNet 5010G is equipped with IEEE 802.3ad Link Aggregation Control Protocol (LACP), which provides a method for controlling the bundling of several physical ports together to form a single logical channel. Two or more Fast Ethernet or Gigabit Ethernet connections are combined in order to increase the bandwidth and to create resilient and redundant links.
Another novel feature is ‘auto-elect ring master’ functionality. Most other managed Ethernet switches employ a master-slave relationship across a network ring, which requires the appointment of a master switch and slave units. The problem here is if the master switch fails, the consequences can be disastrous. With the JetNet 5010G, each switch on the network is defined by its Media Access Control address (a unique ID number). If the elected master switch fails, the master tag is passed to the next highest priority weighted switch and this unit becomes the new master.
Other JetNet 5010G features include modular design, excellent connectivity, environmental protection, power supply redundancy, high port density and Gigabit SX multi-mode 550M, LX single-mode 10km or more, as well as 1,000Mb/s fibre. Gigabit fibre technology offers noise immunity, greater cable distances and electrical isolation. A range of fibre optic cabling options is provided, with ranges up to 2km (multi-mode) and up to 30km (single mode).
As well as fibre optic ports, the device also offers three Gigabit copper ports, facilitating mixed copper and fibre optic media, and allowing the use of copper between lower cost network devices if desired.